1. Field of the Invention
The invention relates to an exhaust-gas treatment unit for a motor vehicle, preferably for close-coupled use.
2. Related Art
For the increasing demands in the field of exhaust-gas treatment, it is necessary for an as far as possible homogeneous exhaust-gas mixture to be produced in a small space, such that optimum treatment of the exhaust gas can be achieved. For an SCR exhaust-gas treatment body (selective catalytic reactor) in particular, it is necessary to achieve good mixing of exhaust gas and added reducing agent, such as in particular a urea-water solution, over the entire (catalytically active) cross-sectional area of the SCR exhaust-gas treatment body.
Furthermore, it must be taken into consideration that the exhaust gas generated by modern internal combustion engines in the automotive engineering sector is relatively cool, and thus, for certain conversion reactions of the exhaust-gas treatment, it is advantageous for the exhaust-gas treatment body to be accommodated in a close-coupled position.
An already-established exhaust-gas treatment unit for close-coupled use emerges for example from WO 2010/142647. By way of the laterally overlapping arrangement of the exhaust-gas treatment units, it is possible to realize a particularly compact exhaust-gas treatment unit.
In the prior art, various other close-coupled concepts are also known, which however appear to still have potential for improvement with regard to their structural size, the homogeneity of the inflowing exhaust gas and/or the distribution of the exhaust-gas components over the cross-sectional area of the exhaust-gas treatment body.